Fuel Pressure Regulator, Die Cast, 4-1/2 to 9 psi, In-Line, 3/8 in NPT Inlet, 3/8 in NPT Outlet, 3/8 in Return, 1/8 in NPT Gauge Port, Bypass, Aluminum, Chrome, Gas, Each. A leader in fuel systems for over 100 years, Holley fuel management systems have powered top circle track and drag racing teams around the world. Now, Holley offers EFI systems for GM’s LS engine, among many other applications. Holley’s products also include performance fuel pumps, intake manifolds, and engine accessories products for street performance, race, and marine applications. FUEL PRESSURE REGULATOR BY-PASS STYLE 6PSI. 2.00 lbs 0.91 kg. 4 in 10.16 cm. 3.5 in 8.89 cm. 2.5 in 6.35 cm. Fitting 1 Side A Size. Fitting 1 Side A Style. Fitting 1 Side B Size. Fitting 1 Side B Style.